class BaseError(Exception):
    _info = None

    def __init__(self, ErrorInfo=None):
        self._info = ErrorInfo or self._info

    def __str__(self):
        return self._info
class ELT(BaseError):

    def __str__(self):
        return 'self.error'
def t1():
    def test():
        raise ELT
    try:
        test()
    except Exception as e:
        print(str(e))
    print('t1')

print(t1())